1. Field of the Invention
The present invention relates to an assembling technique of a retainer to a valve stem of an intake valve or exhaust valve of an engine.
2. Description of the Related Art
A retainer is attached to a valve stem via a cotter. The cotter is a member which engages with an engaging groove formed on the valve stem, and includes a pair of cotter segments. In general, in an apparatus for assembling a retainer to which a cotter has already been assembled to a valve stem, cotter segments are pushed up from the retainer to open the cotter segments, and a valve stem is inserted between the cotter segments. Then, the cotter segments are engaged with an engaging groove of the valve stem, and are then returned to the retainer, thereby assembling the retainer to the valve stem (for example, Japanese Patent Laid-Open No. 10-61420 and Japanese Patent No. 4033703).
Upon pushing up the cotter segments from the retainer, when the cotter segments turn over or when the pair of cotter segments have nonuniform postures, this results in an engagement failure between the engaging groove of the valve stem and the cotter segments.
In an apparatus of Japanese Patent Laid-Open No. 10-61420, only a retainer hole supports the pushed-up cotter segments, and the cotter segments unwantedly have unstable postures. In an apparatus of Japanese Patent No. 4033703, a holding mechanism which holds the cotter segments is arranged to be able to stabilize the postures of the cotter segments, but the apparatus arrangement is complicated.